The invention relates to a precision reference voltage source as generically defined by the preamble to the main claim.
Increasingly stringent demands are made in terms of the characterizing data of monolithically integrated circuits for the motor vehicle. Because of the wide temperature range from -40.degree. C..ltoreq.Tj.ltoreq.+150.degree. C. and above, reference voltage sources with an extremely small or definedly predeterminable temperature coefficient (TK) and low piezoelectric sensitivity are especially important.
From the article by G. C. M. Meijer, P. C. Schmale and K. van Zalinge, "A New Curvature-Corrected Bandgap Reference" in IEEE Journal of Solid-State Circuits, Vol. SC-17, No. 6, Dec. 1982, A precision reference voltage source of the generic type of the main claim is already known; it contains 47 components on a chip area of 4 mm.sup.2 and requires an IC manufacturing process using nickel-chromium resistor technology. Its temperature coefficient is given as 50 ppm in a temperature range of 25.degree. C..ltoreq.Tj.ltoreq.85.degree. C.
The article by A. P. Brokaw, "A Simple Three-Terminal IC Bandgap-Reference" in IEEE Journal of Solid-State Circuits, Vol. SC-9, No. 6, December 1974, already discloses a monolithically integrated reference voltage source operating by the bandgap principle, which includes 29 components on a chip area of 1.47 mm.sup.2 and is likewise produced by nickel-chromium resistor technology. Its temperature coefficient is given as 5 to 60 ppm for a temperature range from -55.degree. C..ltoreq.Tj.ltoreq.125.degree. C.